Core C: Imaging. The goals of this program are to extend our understanding of the biology and application of adjuvant immunotherapies for HIV and SIV infection. The role(s) of the imaging core are diverse. In summary we will examine protein expression by dendritic cells, examine dendritic cell trafficking and location within tissue systems, and define morphologic and immunocytochemical markers for different populations of DCs. We will quantify DNA delivery, integration and expression in cell and tissues following biolistic delivery. Furthermore, we will be involved in a variety of morphometric and immunohistochemical analyses of protein expression in other tissue and cell systems. These investigations will vary from the low resolution studies of whole tissues, defining cell tracking, to high resolution observations of successful gene incorporation as well as subcellular passaging and presentation of protein. The Center for Biologic Imaging, in which this core service will be performed, is designed specifically to perform these activities. It is equipped to perform a continuum of optical methods including all types of light and electron microscopy essential to this program project. Within the scope of this project at the light microscopic level these include: histological, immuno histological, laser confocal, live cell and in situ hybridization technologies. At the electron microscopic level we will provide fine structural and immuno-electron microscopic evaluation of specimens as a natural extension of the light microscopic analyses when needed.. Furthermore, our considerable experience in computerized image processing and morphometry will allow quantitative analysis of observed phenomena to corroborate earlier, possibly quite subtle qualitative changes. This core will be used extensively by all projects, through the imaging tools used will vary from project to project. Preliminary data have shown the validity of these approaches, and we expect a very significant increase in the use of optical techniques with the formal setting of this program.